Folding lifting booms



.June 28, 1955 N, HURsT 2,711,803

FOLDING LIFTING BOOMS Filed Feb. 5, 1952. 3 Sheets-Sheet l AT TORNEY June 28, 1955 N. F. HURST 2,711,803

FOLDING LIFTING BOOMS Filed Feb. 5, 1952 3 Sheets-Sheet 2 NORMAN F. HU'RST E AWN."

ATTORNEY June 28, 1955 N. F HURST FOLDING LIFTING BOOMS 3 Sheets-Sheet 3 Filed Feb. 5, 1952 ZNVENTOR.

NORMAN F HU RST United States Patent FOLDING LIFTING BOOMS Norman F. Hurst, Aurora, Oreg., assignor, by mesne assigumeuts, to McCabe-Powers Auto Body Co., St. Louis, 11 10., a corporation of Missouri Application February 5, 1952, Serial No. 270,061

4 Claims. (Cl. 189--11) This invention relates to improvements in folding lifting booms and is particularly adapted to be mounted on service trucks having to do with electric transmission lines, telephone lines and the like.

The primary object of the invention is to mount a lifting boom on a service truck that can be folded or stored i over the top of the service truck by power'means, as for instance hydraulic cylinders, and that can be brought into operating position by the said cylinders by simply operating hydraulic control valves associated with a hydraulic pumping system on the service truck.

Another object of the invention is to be able to operate the boom from storage or folded position to operating position, or vice versa, by an automatic locking mechanism securing the boom in either position without any manual locking or unlocking of the same.

A still further object of the invention is the construction of a power operated boom that can be lowered sufficiently to pass under wires crossing streets or roads in the operation of the truck.

These and other incidental objects will be apparent in the drawings, specification and claims.

Referring to the drawings:

Figure 1 is a side view of a service truck having my new and improved lifting boom mounted thereon, showing the same in folded or stored position.

Figure 2 is a rear view of the truck, showing the boom in a vertical position at a point where the same is transferred from either folded position into operating position, or from operating position into folded or storage position.

Figure 3 is an enlarged detail sectional view of the lower leg of the boom, illustrating the mechanism for holding the boom in either operating position or storage position.

Figure 4 illustrates the boom being moved from storage position into operating position, the same being locked to the lower pivot point.

Figure 5 is a detail sectional view, taken on line 5---5 of Figure 3.

Figure 6 is a detail sectional view, taken on line 6-6 of Figure 3.

Figure 7 is another preferred boom operating mechanism, part of the truck broken away for convenience of illustration, and showing the boom about to be connected to its lower pivot for operating.

Figure 8 is a rear view of Figure 7.

Figure 9 is a plan fragmentary view, taken on line 9-9 of Figure 8.

Figure 10 is another preferred method of pivoting the boom to the truck wherein pins are used, placeable and removable by hand.

Figure 11 is still another preferred form of locking the boom on either of the two pivot points.

Figures 12 and 13 are fragmentary sectional views taken along lines 1212 and 13--13, respectively, of Figure 11.

Referring more specifically to the drawings:

My new and improved lifting boom for service trucks is Patented June 28, 1955 ice mounted to the truck 1 in the following manner. I have illustrated an A-shaped boom 2, consisting of the legs 3 and 4 being spaced apart by any number of spacer bars 5. The boom is pivotally mounted to the truck 1 by either of the pivot pins 6 or 7 which are disposed at different elevations.

These pivots 6 and 7 are fixedly mounted within the brackets 8 and 9 respectively, the said brackets being fixedly connected to the truck, the brackets 9 being mounted on the bed or deck of the truck and the brackets 8 being mounted on the upper part of the side frames or body of the truck. Forming part of the lower ends of the legs 3 and 4 are open bearings in the form of jaw-like members 10 and 11, which are adapted to embrace the pivot pins 6 and 7, as best illustrated in Figures 3, 4, 5 and 6.

Referring particularly to Figure 3, the boom is in a vertical position having been pivoted from the position shown in Figure 1 and about to be brought to the position in Figure 4. A locking bar 12 is slidably mounted within the openings or bearings 13 formed within the jaws 10 and 11.

The bar is held in the position shown in Figure 3 by the spring latch 14 while the boom is being pivoted about the pivot pin 7 in the position shown in Figure 1. But when the boom is forced to the vertical position by the hydraulic jacks 15, the pawl 16 of the spring bar 14 is released from the pawl 17 formed on the bar 12 by the end 18 of the spring latch being forced to the position shown by the action of the jaw 11 embracing the pivot pin 6,

On further movement of the boom to the position shown in Figure 4, the pivot 7 will force the locking bar 12 downwardly to the position shown in Figure 4 by contacting the inclined surface 19 of the locking bar, forcing the inclined surface 20 against the pivot pin 6 as illustrated in Figure 4, at which time the pawl 21 of the spring latch 22 will engage the pawl 23 of the locking bar 12 holding the inclined surface 20 of the bar against the pivot pin 6, preventing the jaw 11 from becoming disengaged from the pivot 6 in the operation of the boom. This all takes place automatically.

When it is desired to bring the boom into the storage position as indicated in Figure l, the hydraulic jacks will pull the boom to the position shown in Figure 3, at which time the spring latch 22 will be forced to the position shown in Figure 3, unlocking the locking bar 12 and the further movement of the boom will bring the bar to the position shown in Figure 3 by the action of the lower pivot pin, forcing the bar upwardly until the spring latch 14 will cause the pawl 16 to engage the pawl 17 of the locking bar, holding the inclined surface 19 against the pivot 7 while the boom is being swung about the said pivot 7.

The piston rods 24 of the jacks 15 are pivotally connected to the boom, as by means of a cross-bar 5 intermediate the length of the boom, and the opposite ends of the jacks are pivotally connected to the frame 25 by pivots 26, the said frame being secured to the body of the truck by any suitable manner. Extending upwardly from the frame 25 are brackets 27, between which the boom rests while being stored.

In the operation of the boom, fluid is supplied to the cylinder 15 from a suitable control valve from a hydraulic pumping mechanism not here shown, by way of the piping 28 and 29. When the operator desires to raise the boom to operating position, hydraulic fluid enters the pipe 29 from the control valve, forcing the boom to the vertical position, at which time the jaws 10 will be released from the pivots 7 by the locking bars 12 and the jaws 11 will be engaged and locked to the pivots 6 by the said locking bars automatically. Therefore, one man can operate this boom with ease and safety.

In the form of operating mechanism illustrated in Figures 7, 8 and 9, the construction of the boom 2 is substantially the same as the above described boom, except that the hydraulic cylinders are eliminated. The working cable 30 is removed from the sheave 31 and connected to the bottom cross member 32 of the boom 2 by the lifting hook 33 being connected to the anchor bracket 34, which is fixedly secured to the cross member 32. A guy line 35 is trained about the hoisting drum 36 and is dead ended to the upper end of the boom at 37. This line raises and lowers the boom about its lower pivots 6.

I will now describe how the boom is operated. When the hook 33 is entered into the anchor bracket 34, as illustrated in the broken line position Figure 7, and the line reeled on to the drum 38, it will pull the lower end of the boom into engagement with the pivots 6. Simultaneously therewith the drum 36 will pay the guy line 35 out and on the slackening completely of this line the jaws will release from the pivots 7, the weight of the boom 2 forcing the locking bars 12 behind the pivots 6 as above described, permitting the jaws 10 to release from the pivots 7, after which the guy line 35 will support the weight of the boom at any desired angle.

When the jaws 11 are locked to the pivots 6, the hook 33 can be removed from the anchor bracket 34 and threaded through the sheave 31, where it will operate in raising and lowering equipment in the usual manner by the operation of the drum 38.

When it is desired to place the boom in the broken line or inoperating position, the book 33 is again hooked into the bracket 34 and the guy line 35 will be reeled on the drum 36, forcing the jaws 10 over the pivots 7 and releasing the jaws 11 from the pivots 6. The working line 30 being unreeled from the drum 3% to correspond to the rewinding of the drum 36 until the boom is in the broken line position.

I have illustrated my new and improved folding lifting boom being operated by either hydraulic cylinders or by cables associated with lifting drums, but the boom pivot locking means may be the same in either event. My new and improved boom can be mounted to the front end of the truck and will operate equally as well as the rear end mounting. In many cases there is an advantage of mounting the boom to the front of the truck.

Referring to Figure 10, I have illustrated a manual means for locking the pivot points of the boom. I11 this figure the boom is shown in stored position, having a removable pin 50 acting as a pivot. The ear 51 forming part of the boom 2 is pinned to the bracket 9 by the said pin 59, the operator of the truck inserting the pin or removing the same.

When the boom is brought into operating position the ear 51A enters the bracket 8, the operator removes the pin 50 from the bracket 9 placing the same through the hole 52 of the bracket 8 and the hole 53 of the car 51 by hand, or vice versa, in the storing of the boom. This is a simple method but of course it is not automatic. It would require more help in order to erect or store the boom.

In Figure 11, I show still another preferred manually v actuated means for alternatively locking the boom to one or the other of the pivot pins 6, 7. In this embodiment, the jaws 10, 11, are respectively provided with. bores 10', 11, and slidably mounted in said bores 10', 11, at its upper and lower ends respectively is a lockingbar 55, which is of such length as to extend closurewise across one or the other of the jaws 10, 11. In other words, when the locking bar 55 is shifted upwardly to the position shown in Figure 11, its upper end will abut against the downwardly presented face of the top portion of the jaw 10, so that the upper portion of the bar 55 will extend across the jaw 10 and hold the jaw in locked engagement with the pivot pin 7. Meanwhile, the lower end of the locking bar 55 is displaced upwardly so that the lower jaw 11 is not locked around the pivot pin 6 and can swing outwardly to the position shown in Figure 1 about the pivot pin 7 as an axis. Rigidly mounted on the locking bar 55 and extending outwardly at right angles thereto is a tubular sleeve 55' and operatively mounted therein is a conventional latch bolt 56 which is normally positioned inwardly for optional engagement with one or the other of the detent shoulders 57, 58, formed on a locking dog 59, which is, in turn, rigidly welded to the face of the derrick leg 3. When the locking bar 55 is in upwardly shifted position as shown in Figure 11, the locking bolt 56 is engaged with the locking shoulder 57. When, however, it is desired to swing the boom 2 outwardly around the pivot pin 6 as an axis, the locking bolt 56 is manually pulled to the left (reference being made to Figure 11), disengaging it from the shoulder 57. Thereupon, the locking bar 55 can be shifted downwardly so that its lower end extends in locking position across the jaw 11 and, at the same time, the upper end of the locking bar 55 will be shifted downwardly with respect to the jaw 10, so that the pivot pin 7 is no longer in locking engagement in the jaw 10. When the locking bar 55 has reached its downwardly shifted position, the bolt 56 may be shifted into engagement with the shoulder 58.

What I claim is:

1. A folding boom hoisting apparatus comprising a support member, a boom member, pivotal connections at different elevations between said members and including upper and lower horizontal pivots on one of said members and correspondingly positioned upper and lower open bearing elements on the other of said members, said boom being adapted for swinging movement between a folded substantially horizontal position on the upper pivotal connection and an extreme operative position on the lower pivotal connection, first locking means associated with the upper bearing element for optionally closing the bearing element around the upper pivot when it is engaged therewith, second locking means associated with the lower bearing element for optionally closing said bearing element around the lower pivot when it is engaged therewith, means operatively connecting said first and second locking means for alternate operation, whereby one of said locking means is in locked position when the other locking means is in unlocked position, and latch means operatively associated with the first and second locking means or selectively retaining the interconnected first and second locking means in either of said alternate positions.

2. An apparatus as defined in claim 1 wherein said latch means comprises a manually operable bolt operatively associated with said interconnected first and second locking means and dogs fixedly mounted on the member which carries said upper and lower heating elements, said dogs being positioned for alternative engagement with the bolt when the locking means are in one or the other of said alternate positions.

3. An apparatus as defined in claim 1 wherein said first and second locking means are provided with cam surfaces at their ends for engagement with the respective pivot to cam said first and second locking means into one or the other of the alternate locked positions, whereby to alternatively lock one or the other of the bearing elements on the pivot with which it is operatively associated, and said latch means comprising a latch element adjacent each bearing element and operable to release said interconnected first and second locking means by engagement with the respective pivot when the pivot is moved into the respective bearing element.

4. An apparatus as defined in claim 1 wherein said bearing elements each comprise a pair of jaws, the facing jaw elements of the two pair of jaws each having an opening therein and wherein said interconnected first and second locking means comprise a bar, said bar having its ends slidable in said jaw openings and being of a length to extend between said facing jaws and operatively span one of said pair of jaws, the ends of said bar having inwardly facing inclined cam surfaces for engagement by the respective pivot upon movement of the boom 5 6 away from said pivot to earn the bar to close the other latch element and permit said bar to move into closing pair of jaws around the other pivot, said latch means comr laticn with Said jaws. prishgg a a of fi mounted jaw bcarrying References Cited. in the file of this patent mem er an res ective y carrying a atc mem er, sai bar having a lach element adjacent each end thereef 5 UNITED STATES PATENTS for cooperation with the adjacent spring latch member 1,433,272 Govin Oct. 24, 1922 to retain the opposite end of the bar in jaW closing rela- 1,735,408 Nein Nov. 12, 1929 tion, the free ends of said springs respectively extending 1,896,203 Rosatelli Feb. 7, 1933 between the adjacent jaws to be engaged by the respec- 2,354,922 McEWen Aug. 1, 1944 tive pivot upon relative movement into its respective jaw 10 2,541,970 Pospisil Feb. 13, 1951 and release the respective latch member from the adjacent 2,611,580 Troche et al. Sept. 23, 1952 

